Recent years have seen considerable advances in the dynamic information presentation marketplace, particularly with regard to the use of plasma display technology. Conventionally, the dynamic advertising market uses networked plasma-based display systems because of its excellent optical characteristics, thin profile and wide viewing angle. Since the original commercial introduction of 42-inch plasma display products, use of this technology as a “Digital Ad Board” has become fairly commonplace. In a Digital Ad Board application the entire screen is typically used to display an “ad loop,” or a series of full-screen advertisements that cycle on a regular basis.
One peculiarity of plasma display technology is its tendency to “burn in” if a static image is displayed in the same location over a continued period of time. This burn-in is a physical property of plasma display technology and is not likely to be eliminated through core technology advancements. The burn-in is caused by a natural degradation of the amount of light output the phosphor chemicals emit as they continue to be “excited” over time, and translates to a “ghost image” when the same image is displayed in the same location for a prolonged period. When a static image like this is displayed, pixels that were “on 100%” (displaying white) would be degrading at the maximum rate while pixels that were “turned off” (displaying black) would not be degrading at all. Over time, after these two groups of pixels were displaying the same color, a noticeable variation in light output for the two groups occurs and the ghost image becomes recognizable.
For Digital Ad Board applications, this characteristic is not too problematic as long as the ad segments that comprise the ad loop represent sufficient variation over the cycle so as to approach a fully dynamic (random) presentation at each pixel of the display. In practice, this would translate to setting a maximum duty cycle of 1% or so for any given image (depending on the native characteristics of the particular plasma display used, the color gradation of the images, the frequency of changes of the ad loop itself, and whether any image spiraling techniques were used to reduce the native burn rate). The net result of a fully dynamic ad loop is that all pixels of the display would degrade roughly the same amount over time, and no ghost effect would be noticed.
For digital signage applications other than Digital Ad Boards (“General Purpose Digital Signage”), the impact of burn-in is far more pronounced. In these applications, at least some portion of the display is not presenting a series of images or video; rather, it would generally include some fixed or pseudo-fixed images that would be present over an extended period of time. For example, as a Flight Information Display in an airport or as a Digital Menu Board in a quick service restaurant, there are generally fixed text fields and frequently fixed text that would be displayed; generating random location patterns is simply not practical in most cases. For these applications, the effect of burn-in becomes dramatic and, in many cases, would prevent the use of plasma technology. Furthermore, eliminating plasma display technology from consideration limits the use of digital displays at all in many of these applications since there are currently no other practical alternatives.
In order to reduce the rate of burn, some plasma manufacturers have incorporated electronics that periodically shifts the image around in a spiral or other pattern, usually within a 5 pixel radius. Although this technique reduces the rate of burn-in, it does not eliminate it; additionally, it introduces a noticeable and distracting movement of the screen image which is particularly noticeable when the user is reading text at the time of the movement.
Furthermore, Digital Menu Board applications generally have zero tolerance to down time; if the menu is not visible the patrons cannot effectively place orders and the entire operation can be sidetracked. Given the typical layout of traditional menu boards that include menu lists (critical) and promotional images (non-critical) content, it is possible to construct a system for multiple display installations that can automatically recover from a single-unit hardware failure by redeploying critical information to the remaining display(s). By doing so, this fault-tolerant design addresses the most critical issue currently stifling the conversion to a digital paradigm: what if the hardware fails?
Wayfinding is one specific digital signage application that utilizes interactive plasma (or other large-screen) display technology to deliver facility directory and other relevant information services. As described in the related U.S. Patent Application Publication Nos. 2002/0078459 and 2002/0165781, the user interface architecture must be conducive to intuitive operation and must blend the generally divergent influences of information and advertising components (when a hybrid advertising/public information model is being used). The marketplace has demonstrated unequivocally that user acceptance of interactive public information systems is paramount to their commercial success, and to date few products of this kind have succeeded even though many have been tried.
Because of the fact that wayfinding users are in a transient mode within a public space, small delays that might be acceptable in a desktop interface may cause the user to disengage in a wayfinding environment. In order to achieve intuitive operation, the interface design must be focused and elements must be carefully chosen so that new users to the system are able to navigate to the desired information quickly and with minimal effort. In order to achieve the desired result, one must focus on three main areas of the interface design:                “Default Screen” architecture. This is the interface displayed while the system is not in use.        “Content Presentation” architecture. This is the interface displayed after the system is engaged by the user.        “Navigation Feedback Mechanisms.” These are visual and audio elements incorporated into the navigation sequence to assist the user in quickly understanding what information is being presented and what additional information is available.        
In view of the foregoing, there remains a need in the art for enhanced display panels and associated apparatus and methodology for driving such display panels.